The 2016 25A model had a fix mount. So, I replaced it with the articulating arm. I think I ended up drilling new holes on the bump out square Airstream mounting piece of wood. I glued the back of the new mount plate with Sikaflex 221 and then attach with the supplied bolts.
I'm in the process of changing out the OEM articulating arm in the bedroom with a similar TV mount but without the tilting function (the old one is now in a permanent tilt) -- too much vibration in the back. I'm also replacing that 24 inch Samsung (120v AC power) with a Jensen 24 inch
12v DC powered TV-- that way, I don't have to run inverter when dry camping. I already installed a
12v plug (cigarette lighter) previously behind the TV mount to run a
12v floor fan. Good luck on the install!